Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems (1921)
Smith, Arthur Bessey, b. 1875, Campbell, Wilson Lee · New York : McGraw-Hill · leaf 337
L:> To Automatic- Switchboard … Fig. 263.—Simplex controlling circuit for rural party line. battery. The line relay controls the loop-dialing circuit to the auto-matic switches. When the receiver is taken from the hook, the line relay pulls upand closes the line to the automatic switchboard. The operation of thecalling device is…
Telephone
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